My W is the same way concerning the kids' behaviour. She is constantly riding them about something. Especially meal time. The days that she is gone or the mornings I get them ready alone, meals are good. We catch up with one another. We laugh. We talk. When W is here, we are supposed to eat, be quiet and get done. Good family time, huh?
I guess the roller coaster will only get as bad as you let it. You seem to be in the right mindset to do what you need to do. Don't let fear control you as I have, it will only defeat you.